Abstract: The majority of American women transitioning through the menopause will experience hot flashes. However, safe and effective treatments for hot flashes are currently lacking. Investigation of new treatments for hot flashes has been limited by the measurement of hot flashes. Current gold standard physiologic measures of hot flashes have key limitations, including electrode design, monitor size, and data storage capabilities that result in poor user interface, discomfort, interference in activities and sleep, and short monitoring durations. The first Phase I specific aim is to develop an improved ambulatory sternal skin conductance monitoring device that is highly wearable and unobtrusive, has increased data storage, and has a simplified user interface. This device would utilize novel electrodes, designed with the capability to be easily detached and reattached by the user. The device would include a wearable, sensor module that processes the sternal skin conductance signal. Data will be stored on a flash card and signal processing will be done to detect criterion skin conductance changes. The second phase I specific aim is to validate the measurement device in a laboratory and ambulatory setting relative to the existing gold standard physiological measurement device for hot flashes. This validation will include establishing criterion skin conductance changes and the laboratory sensitivity and specificity of device. The development of a valid, unobtrusive hot flash measurement device suitable for long-term monitoring can serve as a tool for the accurate measurement of hot flashes. This device can thereby aid in the subsequent development of effective treatments for hot flashes to improve the quality of life of the majority of women.